// Tencent is pleased to support the open source community by making RapidJSON
// available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All
// rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file
// except in compliance with the License. You may obtain a copy of the License
// at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#ifndef RAPIDJSON_STRINGBUFFER_H_
#define RAPIDJSON_STRINGBUFFER_H_

#include "internal/stack.h"
#include "stream.h"

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
#include <utility>  // std::move
#endif

#include "internal/stack.h"

#if defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(c++ 98 - compat)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Represents an in-memory output stream.
/*!
    \tparam Encoding Encoding of the stream.
    \tparam Allocator type for allocating memory buffer.
    \note implements Stream concept
*/
template <typename Encoding, typename Allocator = CrtAllocator>
class GenericStringBuffer {
 public:
  typedef typename Encoding::Ch Ch;

  GenericStringBuffer(Allocator *allocator = 0,
                      size_t capacity = kDefaultCapacity)
      : stack_(allocator, capacity) {}

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
  GenericStringBuffer(GenericStringBuffer &&rhs)
      : stack_(std::move(rhs.stack_)) {}
  GenericStringBuffer &operator=(GenericStringBuffer &&rhs) {
    if (&rhs != this) stack_ = std::move(rhs.stack_);
    return *this;
  }
#endif

  void Put(Ch c) { *stack_.template Push<Ch>() = c; }
  void PutUnsafe(Ch c) { *stack_.template PushUnsafe<Ch>() = c; }
  void Flush() {}

  void Clear() { stack_.Clear(); }
  void ShrinkToFit() {
    // Push and pop a null terminator. This is safe.
    *stack_.template Push<Ch>() = '\0';
    stack_.ShrinkToFit();
    stack_.template Pop<Ch>(1);
  }

  void Reserve(size_t count) { stack_.template Reserve<Ch>(count); }
  Ch *Push(size_t count) { return stack_.template Push<Ch>(count); }
  Ch *PushUnsafe(size_t count) { return stack_.template PushUnsafe<Ch>(count); }
  void Pop(size_t count) { stack_.template Pop<Ch>(count); }

  const Ch *GetString() const {
    // Push and pop a null terminator. This is safe.
    *stack_.template Push<Ch>() = '\0';
    stack_.template Pop<Ch>(1);

    return stack_.template Bottom<Ch>();
  }

  //! Get the size of string in bytes in the string buffer.
  size_t GetSize() const { return stack_.GetSize(); }

  //! Get the length of string in Ch in the string buffer.
  size_t GetLength() const { return stack_.GetSize() / sizeof(Ch); }

  static const size_t kDefaultCapacity = 256;
  mutable internal::Stack<Allocator> stack_;

 private:
  // Prohibit copy constructor & assignment operator.
  GenericStringBuffer(const GenericStringBuffer &);
  GenericStringBuffer &operator=(const GenericStringBuffer &);
};

//! String buffer with UTF8 encoding
typedef GenericStringBuffer<UTF8<>> StringBuffer;

template <typename Encoding, typename Allocator>
inline void PutReserve(GenericStringBuffer<Encoding, Allocator> &stream,
                       size_t count) {
  stream.Reserve(count);
}

template <typename Encoding, typename Allocator>
inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator> &stream,
                      typename Encoding::Ch c) {
  stream.PutUnsafe(c);
}

//! Implement specialized version of PutN() with memset() for better
//! performance.
template <>
inline void PutN(GenericStringBuffer<UTF8<>> &stream, char c, size_t n) {
  std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
}

RAPIDJSON_NAMESPACE_END

#if defined(__clang__)
RAPIDJSON_DIAG_POP
#endif

#endif  // RAPIDJSON_STRINGBUFFER_H_
